Evolving Disks in Cold Dark Matter Cosmology

Abstract

Despite having entered the era of "precision cosmology," the formation of galaxies within the favored CDM cosmological paradigm remains problematic. By relating our N-body/smooth particle hydro-dynamical simulation to an extensive range of Galactic and extragalactic observations, we shed light on the formation and evolution of the Milky Way and other late type galaxies. In light of recent observations of the stellar populations of extragalactic thick disks, we examine the proposal that the thick disk formed in a high redshift period characterized by gas rich merging. We show such a scenario to be consistent with color observations. We then follow the evolution of structural parameters of the subsequently formed disk galaxy, from redshift ~1 to the present. Consistent with observation, little evolution in the ratio of scale-height to scale-length is found in our simulated galaxy, despite its somewhat chaotic origins. The simulated galaxy in this report forms part of a larger study of a suite of galaxies, with which these issues are to be studied in detail.